1. Field of the Invention
The present invention relates to high efficiency transmitters, and more particularly to transmitters that allow improvement of efficiency of power amplifiers (PAs), relaxing of timing requirement, and realization of reduction in size of circuits.
2. Description of Related Art
Demand for high efficiency transmitters is increased so as to enable long time phone call communication or extension of battery duration in wireless communication devices. As high efficiency transmitters, for example, transmitters using polar modulation mode have been known to date. However, in the polar modulation mode, two modulation paths for amplitude modulation and phase modulation are connected to a PA. Therefore, there is a problem that cost is increased for timing synchronization therebetween.